Structure and UV-Vis spectroscopy of the iron-sulfur dinuclear nitrosyl complexes [Fe2S2(NO)4]2? and [Fe2(SR)2(NO)4]

AbstractIron-sulfur (FeS) proteins are ancient and fundamental to life, being involved in electron transfer and CO2 fixation. FeS clusters have structures similar to the unit-cell of FeS minerals such as greigite, found in hydrothermal systems linked with the origin of life. However, the prebiotic pathway from mineral surfaces to biological clusters is unknown. Here we show that FeS clusters form spontaneously through interactions of inorganic Fe2+/Fe3+ and S2− with micromolar concentrations of the amino acid cysteine in water at alkaline pH. Bicarbonate ions stabilize the clusters and even promote cluster formation alone at concentrations >10 mM, probably through salting-out effects. We demonstrate robust, concentration-dependent formation of [4Fe4S], [2Fe2S] and mononuclear iron clusters using UV-Vis spectroscopy, 57Fe-Mössbauer spectroscopy and 1H-NMR. Cyclic voltammetry shows that the clusters are redox-active. Our findings reveal that the structures responsible for biological electron transfer and CO2 reduction could have formed spontaneously from monomers at the origin of life.

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Multinuclear NMR and UV–Vis spectroscopy of site directed mutants of the diabetes drug target protein mitoNEET suggest that folding is intimately coupled to iron–sulfur cluster formation

Inorganic Chemistry Communications ◽

10.1016/j.inoche.2015.11.022 ◽

2016 ◽

Vol 63 ◽

pp. 86-92 ◽

Cited By ~ 2

Author(s):

S.K. Benson ◽

K.M. Boyce ◽

R.M. Bunker ◽

N.B. Collins ◽

K.J. Daily ◽

...

Keyword(s):

Drug Target ◽

Cluster Formation ◽

Target Protein ◽

Iron Sulfur Cluster ◽

Sulfur Cluster ◽

Multinuclear Nmr ◽

Iron Sulfur ◽

Vis Spectroscopy ◽

Diabetes Drug

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Nitrosyl Complexes of Iron-Sulfur Clusters

Advances in Inorganic Chemistry ◽

10.1016/s0898-8838(08)60235-4 ◽

1988 ◽

pp. 335-393 ◽

Cited By ~ 91

Author(s):

Anthony R. Butler ◽

Christopher Glidewell ◽

Min-Hsin Li

Keyword(s):

Iron Sulfur Clusters ◽

Nitrosyl Complexes ◽

Iron Sulfur

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ChemInform Abstract: Nitrosyl Complexes of Iron-Sulfur Clusters

ChemInform ◽

10.1002/chin.198852334 ◽

1988 ◽

Vol 19 (52) ◽

Author(s):

A. R. BUTLER ◽

C. GLIDEWELL ◽

M.-H. LI

Keyword(s):

Iron Sulfur Clusters ◽

Nitrosyl Complexes ◽

Iron Sulfur

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Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200201 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20402

Author(s):

Kaoutar Benthami ◽

Mai ME. Barakat ◽

Samir A. Nouh

Keyword(s):

Refractive Index ◽

Optical Properties ◽

Band Gap ◽

Color Difference ◽

Band Gap Energy ◽

Polybutylene Terephthalate ◽

Γ Irradiation ◽

Gap Energy ◽

Vis Spectroscopy ◽

Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

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DETERMINATION OF GLYCOL CONTAMINATION IN ENGINE OIL BY INFRARED AND UV-VIS SPECTROSCOPY

Proceedings of the 73rd International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2018.th10 ◽

2018 ◽

Author(s):

Torrey Holland ◽

Dennis Watson ◽

P Sivakumar ◽

Ali Abdul-Munaim ◽

Robinson Karunanithy

Keyword(s):

Engine Oil ◽

Vis Spectroscopy

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Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽

10.1557/adv.2020.416 ◽

2020 ◽

Vol 5 (63) ◽

pp. 3353-3360

Author(s):

Susana Helena Arellano Ramírez ◽

Perla García Casillas ◽

Christian Chapa González

Keyword(s):

Gold Nanoparticles ◽

Polyethylene Glycol ◽

Room Temperature ◽

Colloidal Stability ◽

Infrared Spectrometry ◽

Ammonium Bromide ◽

Chloroauric Acid ◽

Vis Spectroscopy ◽

Seed Mediated ◽

Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

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